Mac: Thanks for the response. Several of your comments on timing and the Pertronix distributor may be right on. The difficulty did begin with my changing the distributor but I have been wanting to blame something I did rather than the new distributor. I sent an email to Pertornix to get an advance curve but got no answer. I have measured the advance (with the vacuum line to the Weber disconnected) to 2000 RPM. I get 15 degrees advance above the idle (800 RPM) advance but the curve is not smooth. I have had trouble getting repeatable advance measurements with the vacuum line connected. I need to go back this weekend and make that measurement again; including, as you suggested, measurements of the timing stability. My memory of the measurement, several months ago, was that I was getting alot of jumping around as the RPM's increased. I am new at making this measurement and I need to learn to get repeatable values. At that point I would like to continue this thread.
You are right that the engine is "far removed from standard." However the performance was reasonable good before my attempt to "improve" things. Thanks for the help.
BobK